I notcied a nasty, wet black smear on my front rotor after popping some suspension oil around the seals of my forks. I can only assume that I managed to drip some on the rotor (the blackness seems to be residue from the pads. I cleaned the rotor up with meths, popped the pads out and took a good look at them, both appeared dry.
Now I'm wondering whether any contamination will wear/burn off if I continue to use the pads (it's a shame to ditch them as they're pretty new) or whether I ought to play it safe and fit a new set (probably worth cleaning the rotor again too if this is the case).
Try roasting the pads in the oven - if that doesn't work bin them.
You'll soon know if they're screwed when you try to stop so bear this in mind if you decide to carry on with them.
If its surface contamination then sanding them might clean them up. Burning them can work but can also destroy thee bond to the backing plate ( I have had both happen)
If they are contaminated with oil you will know - they wont work! Burning contamination off in use works with motorcycle pads but I am not sure it is easy to get MTB ones hot enough
Blowtorch em,but not so they start to glow!Emery paper the surface and sorted.
you could try a brake/clutch cleaner then give them a sand, worked for me. If you sand them you will need to bed them in again.
Just find a big long steep hill. If we hear from you again you managed to both burn off the contamination and bed them in, if not we will know not to try it ourselves.
ride it and see.